ML20078B544

Forwards Minutes of 821018-19 Meetings W/Util in Bethesda,Md Re Steam Generator Repair Process Update & Return to Svc Overview

ML20078B544
Person / Time
Site:	Three Mile Island
Issue date:	11/18/1982
From:	Shook T FRANKLIN INSTITUTE
To:	Jacobs R, Rajan J NRC
Shared Package
ML20077J956	List: ML20078B544 ML20078B558 ML20078B644 ML20078B646
References
FOIA-83-243 NUDOCS 8309270130
Download: ML20078B544 (3)

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INFORMAL TECHNICAL COMMUNICATION Date U C L/

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To: . TAI RMA N [(2 tC E. TACO 85 From: TED SHDOK U.S. Nuclear Regulatory Commission Franklin Research Center Washington, D.'C. 20555 Philadelphia, PA 19103 (TO BE OPENED BY ADDRESSEE ONLY)

Reference NRC Contract NRO-03-81-130 PRC Project C5506 A 53(GNMrul' to NRC TAC No. FRC Generic Topic T-A41 - l j

Plant TMi-1 FRC Task (s) __

Title:

TRI P RE=POCLT fM n Tw o.-

AT NRC

Attachment:

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Copy of message form only: NOTE TO SENDER: Include ATTeciaavur ro raosc 8 trt.o to ****ch=*at* if inf '"*ti a i*

pertinent to program management.

S. S. Bajwa '

NRC Performance Mcnitor N @ ERT 13 /2A M M FR NRC Lead Project Manager ( OM RAD Me C (2 ACl4"U FRC Distribution: SPC, SP, f, t_ L , M, VL ,g, ,

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[Q- tfr] 8309270130 830629 PDR FOIA DORDSHOB3-243 PDR

[} N Revised 4/20/82 A x' UUdi! Franklin Research Center .

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MEETING REPORT Place: Bethesda, Md. Project C5506

, \ Dates: October 18 and 19,1982 Present: Representatives of GPUN, NRC, and NRC Consultants.

FRC representatives - C. Davey L. Leonard V. Luk T. Shook Purpose of. Meeting:GPUN Presentation of TMI-l OTSG Repair Process Update and Return to Service Overview.

I The presentation was divided into 8 sections. In the first, qualification program update, recent test data was presented. The two major areas of concern here are the pull-out loads and the leak rates. The pull-out data showed all tests indicated pull-out loads greater than the qualification value of 3140 lbs and averaging about 4750 lbs.. The leak data varied over a very wide range. Very few results were within the qualification value of 3.2 x 10-6 lbs/hr per tube; most were within the design value of 3.2 x 10-5 lbs/hr per tube, but some were in excess of that value.

Interestingly, those test blocks subjected to the severest cionditions (after hits and axial loading) showed the lowest leak rate data.

Final eddy current testing (ECT) results were presented, along with a discussion of the relative merits of the two techniques for testing, i.e. , the absolute and the standard differential (SD) technique. The latter was recommended for production testing.

The stability of a tube crack under flow induced vibration is a function of its are length and percent thruwall. The ECT technique has been shown to be able

to detect cracks in the stable region; i.e. , all cracks in the unstable region, (and therefore capable of rapid grc *.h), are detectable by ECT.

The key factors in the plant return .o safe operation were. identified as an under-standing of the failure mechanism, measures being taken to prevent recurrence, RCS and supporting safety system undamaged, steam generators operable, and no adverse environmental impact.

The OTSG tube plugging plan was presented. The following categories of tubes will l be plugged:

1. All tubes with defects in high cross-flow areas.

2. All tubes with defects considered to be in the unstable region.

3. Some tubes with defects in the stable region (to afford later

! crack growth rate studies). ,

le total number designated for plugging is 1146.

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Q W Meeting Report, 10/8-9/82 C5506 - 10000 Plans for sulphur removal are not yet in place. It has also not yet been determined whether the entire primary system will undergo a clean-up, or the* steam generator a alone.

The Licensee plans to conduct a long-term corrosion test program (17 months). It is essentially a laboratory simulation to assess environmental effects on tube performance. The test operational sequences are planned to lead actual OTSG operation at THI-1. ECT will be performed after each test cycle.

_, Details of the post-repair test program were presented. These. include ECT, heat-up I and cool-down, leakage, hot functional tests (HFT), and post-HFT.

All aJpects of the post repair program appear to be reasonable and necessary. There was a brief discussion on whether or not it would be appropriate to conduct ECT following the HFT. (The Licensee does not feel this is necessary.) The NRC invited all consultants to respond to this question.

We feel that eddy-current testing following the hot functionals is unnecessary, and could be , counter-productive. ECT, of course, necessitates a shutdown, which, in turn provides an environment more conducive to further attack than is the case during normal operation. If the long-range objective is to safely operate the OTSGs as long as possible, then it will save time and possible additional damage to follow the HFT directly with power escalation testing, critical and post critical operation.

The pre-critical leakage monitoring should be a sufficient (and, perhaps, the best) indicator of the ability in the near term of the plant to rua safely.

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